On Fri, 12 Jun 2009 15:56:48 -0400, Michael Horowitz
wrote:

I know the compressor requirements are stated when considering a
sandblaster, but is there anyway to measure the effectiveness e.g. is
my blaster taking off paint as quickly as someone elses?

As an example, I can take off an 1/8" strip of paint at about
1"/second, but have no idea what should be happening - Mike

mike I never used this because I did all the error and frustration
stuff that went into this.

save up all of your bead blasting work for one big session and go and
hire yourself a trailer mounted diesel engined compressor.
they are not expensive to hire.
one of the brands in australia is Broomwade.

they have the advantage of being able to deliver 120 to 150psi air all
day long.

bead blasting effectiveness is *all* in the pressure.

at 150 psi and using an el cheapo automotive shop style bead blasting
gun you will be cooking!

the same gun at 60 psi will softly polish the surface and remove
nothing.

I used 3 single phase compressors Teed together in the end and the job
still took me 3 weeks.
my mate took my advise and bead blasted his entire fuselage in 1 day
with no time waiting for a pumpup.

by my reckoning an el cheapo bead blasting gun uses about 60cu ft/min
to be effective. if you stick with what you've got, like me you'll be
forever waiting for a pump up.

btw before you start look at the nozzle on your bead blasting gun.
this *will* wear out and the alloy will be shot into the surface of
your aircraft.
it pays handsomly to go and buy a few feet of nylon rod of the same
diameter as the supplied nozzle. cut it all up into the same lengths
and drill out the centre to the same diameter as the supplied one.
the nylon ones will not damage the aircraft and will last marginally
longer. if you've got a supply it is easy to swap in a new one when
they wear out because they are held in place with a set screw.
also if you are using a lathe. machine a little recess in the end so
that they have a small sharp lip. this is incredibly useful for use as
a scraper for dislodging persistent stuff without having to put the
gun down and take the gloves off.
the second most useful tool in bead blasting is a swiss army knife
with a slightly blunt blade. worlds best beadblasting scraper.

......I have the Tee shirt :-)
Stealth Pilot